1. Field Of The Invention
The present invention relates to a stab-type coupler designed to couple together plastic pipes. The pipes are slid into the coupler around opposite ends of a hollow tube stiffener provided in the coupler, and once inside the coupler, the pipes are held in fluidtight connection therewith by means of boot seals and grippers provided within the coupler.
2. Description of the Related Art
Stab-type couplers are designed to secure together pipes, usually plastic or other non-metallic types of pipes. Often these types of couplers are used at a construction site to fasten together pipes that are being installed underground. In such work environments, it is desirable to have a coupler that employs a minimum number of separate parts that can be dropped or lost. Also, it is desirable that the seal created between the coupler and the pipes be easy to form, for example, by a workman wearing gloves that limit his manual dexterity. In addition, the seal between the pipes and the coupler must be fluidtight, i.e. sealed against leakage of either liquids or gases, and must be secure enough so that the pipes will not become detached once they are coupled.
The present invention addresses these needs by providing a unitary coupler that seals to a pipe simply by sliding an end of the pipe into the coupler, thus forming a fluidtight seal between the pipe and the coupler. Also, the gripping means provided with the present invention is designed so that when external pulling force is exerted onto the pipe in order to remove the pipe from the coupler, the gripping means tightens against the exterior surface of the pipe, thus preventing the pipe from being pulled from the coupler. The tightening action of the gripping means around the pipe functions in a manner similar to the way toy "Chinese Handcuffs" tighten around a child's fingers as the child attempts to pull his fingers out of the Chinese handcuffs; the harder the child pulls, the tighter the Chinese handcuffs tighten around the fingers.
Also, the gripping means of the present invention is designed so that increasing pressure from within the tubes will also cause the gripping means to increasingly tighten around the exterior surface of the pipe, thus preventing the pipe from being blown out of the coupler.